Gas torch



Aug. 30, 1949. Y E. R. BLAHUT' I 2,480,283

' I GAQS TORCH Filed April 8, 1948 3 Sheets-Sheet l INVENTOR EDWIN R, BLAHUT ATTORNEYS Aug. 30, 1949. E. R. BLAHUT 2,480,233

(ms TORCH Filed April 8, 1948 3 Sheets-Sheet 2 \l a? m N 2 x LL N L INVENTOR EDWIN R. BLAHUT BY ATTORNEYS 30, 1949- E. R. BLAHUT 2,480,283

GAS TORCH 3 Sheets-Sheet 3 Filed April 8, 1948 w I lNVENi'OR EDWIN R. BLAHUT BY 4 a Z1 ATTORNEYS only two gas hoses Patented Aug. .30, 1949 GAS TORCH Edwin E. Blahut,

Air Reduction Company,

notation of New York Application April 8, 1948, Serial No. 19,664 9 Claims. (Cl. 158-27.4)

This invention relates to oxy-fuel gas cutting and scarfing torches.

As is well known to those familiar with the art, a ferrous metal work-piece may be cut or gouged (scar-fed) by heating a portion of the work-piece to kindling temperature and then subjecting the heated portion to a high velocity jet of oxygen. All oxy-fuel gas cutting torches are constructed to project a number of preheating flames about the orifice from which the cutting-oxygen issues. The preheating flames are usually fed by a combustible mixture of oxygen and a fuel gas. The most widely used fuel gas for this purpose is acetylene and it will hereinafter be referred to as such, although the term is meant to include any suitable fuel gas. The preheating flames are used for the above-mentioned heating of the metal to kindling temperature, and they are usually left on and projected against the work as the cut progresses because the out can best be propagated by doing this.

The preheating flames are usedalone during the heating of the metal to kindling temperature at the start of the cutting operation and then the cutting-oxygen stream is turned on. The amount of oxygen required by the cutting-oxygen stream is far in excess of that required by the preheating flames. In two-hose torches now in use in which one hose supplies the acetylene and the other hose supplies oxygen for both the cutting stream and the preheating names, the preheat oxygen is tapped off the cutting-oxygen passage in the torch, and when the cutting-oxygen valve is opened the sudden demand of the cutting jet results in a material decrease in pressure of the oxygen delivered to the preheat mixer and disrupts the balance between the oxygen and electylene for the preheating flames. Although this is undesirable because it changes the flame characteristics, it has heretofore been tolerated in this type of torch because of the advantages of having leading to the torch, and to avoid the difficulty it has been necessary to resort to the use of three-hose torches in which one hose supplies the acetylene and the other two hoses separately supply the preheat oxygen and the cutting-oxygen from separate pressure regulators.

The principal object of this invention is to provide a cutting torch which employs only two gas supply hoses and yet maintains substantially constant preheating flames regardless of the rate of oxygen flowing through the cutting orifice.

A cuttin torch embodying the invention Hackensack, N. J., assignor to Incorporated, a corillustrated in the accompanying drawings, in which:

Figure l is a side elevation of the torch;

Fig. 2 is a vertical section through the head and tip of the torch shown in Fig. 1, drawn on an enlarged scale;

Fig. 3 is a side elevation of the body portion of the torch shown in Fig. 1, drawn on an enlarged scale, the cutting-oxygen valve associated with the body portion being shown in vertical section;

Fig. 4 is an enlarged rear end view ofthe torch body; V

Fig. 5 is an enlarged longitudinal section of the torch body taken alon the line 5-5 of Fig. 4;

Fig. 6 is an enlarged bottom view of the torch body; and

Fig. '7 is an enlarged longitudinal section of the torch body taken along the line 1--1 of Fig. 6.

Referring first to Figs. 1 and 2, the torch comprises generally a body Ill, a handle portion H, a head 12, and a tip l3. Acetylene enters the body [0 through a fitting l4 and oxygen enters it through a fitting [5. The oxygen stream divides in the torch body, as described in detail hereinafter, and part of its passes through the cuttingoxygen valve 16 and through tube H to the head torch body I0 which i8 56 end will discharge into thereof in such a way as l2 from which it is delivered to the cutting-oxygen passage 18 in the tip l3. The other part of the oxygen constitutes the preheat oxygen and flows from the body In through valve l9 and tube 2llto the head l2 from which it is delivered to the preheat passages 2| in the tip l3. Acetylene entering the body through fitting l4 passes through a tube 22 to the head I2 from which it enters the tip preheat passages 2| and mixes with the preheat oxygen. All parts thus far referred to are conventional with the exception of the includes novel means for giving the torch its desirable characteristics.

Figs. 3, 4, 5, 6 and '7 are all enlarged views of the torch body. The acetylene passage 23 is drilled straight through the body as is clearly illustrated in Fig. '7. The oxygen enters the body by passage 24. This passage constitutes a portion of the cutting-oxygen passage and is substantially parallel with a preheat oxygen passage 25 (Fig. 5) drilled part way into the torch body from its downstream end. A bore 26 extends transversely into the body portion from one side to intersect the preheat passage. 25 and to meet the cutting-oxygen passage 24. A tube 21 having a snug fit in the bore 26 is inserted into the bore far enough so that one the preheat passage 26 and its other end will project part way into the cutting-oxygen passage 24. The diameter of the bore 26 and the external diameter of the tube 21 are less than the diameter of the portion 24 of the cutting-oxygen passage. After the tube 21 is positioned, the outer end of the bore 26 is closed by means of a plug or other member 28. The end of the tube 21 which projects into the cutting-oxygen passage has an inlet opening by means of which some of the oxygen in the cutting-oxygen passage enters the tube for delivery to the preheat oxygen passage 25, In the preferred construction, the bore 26 is drilled into the body so that it, and also the tube 21, are inclined in the downstream direction from the cutting-oxygen passage to the preheat oxygen passage, as best shown in Fig. 5, and the inlet end of the tube is bevelled as shown at 29 to form an inlet opening in the cutting-oxygen passage which faces upstream therein. The bevelled inlet end of the tube which projects into the cutting-oxygen passage therefore constitutes a preheat oxygen pickup which picks up some of the oxygen flowing in the cutting-oxygen passage and directs it into the preheat oxygen passage 25. It might also be said to constitute baifle means for deflecting some of the cutting-oxygen passing through the cuttingoxygen passage into the preheat oxygen passage.

Beyond the preheat oxygen pick-up tube 21, the cutting-oxygen passage leads to the cuttingoxygen valve l6 and then to the cutting-oxygen tube IT.

The cutting-oxygen valve is shown in section in Fig. 3. It comprises a valve seat 30 formed on a portion of the torch body itself. The remainder of the valve assembly is screwed into an internally threaded boss 3| on the torch body. The valve element is shown at 32. The one illustrated is the molded rubber diaphragm type, but any other suitable valve. element may be used. Actuation of a lever 33 (see also Fig. 1) in a clockwise direction about a fixed pivot 34 causes withdrawal of a valve stem 35 and the valve element 32 from the valve seat 30 against the action of a coil spring 36. This permits the flow of cutting- ,preheat oxygen and the fuel oxygen past the valve element. Upon release of lever 33 the coil spring 36 expands and reseats the valve element, thereby stopping the flow of cutting-oxygen. The cutting-oxygen valve has been only briefly described because it does not form a part of the invention.

If the preheats oxygen were delivered from the cutting-oxygen passage to the preheat oxygen passage through an ordinary passage that does not have the tube 21 or its equivalent, there would be a substantial oxygen flow into the preheat oxygen passage 25 when the cutting-oxygen valve I6 was closed and a. greatly reduced flow when it was open. This is true because the total head at any point in a fluid stream is equal to the sum of the pressure head and the velocity head. With the cutting-oxygen valve closed the energy of the stream is practically all pressure head, the flow of the preheat oxygen being practically negligible. This relatively large pressure head would provide an adequate supply of preheat oxygen to the preheat oxygen passage from the cutting-oxygen passage. cutting oxygen reheat oxy fin supplied through the ordinary passage leading to the preheat oxygen passage. When a pick-up tube of the kind above described.

76 ting-oxygen passage and being so 4 or its equivalent, is employed, and the cuttingoxygen valve is closed, approximately the same amount of oxygen will flow through the tube as would flow through the ordinary tubeless passage under the same conditions. However, when the cutting-oxygen valve is open flows, the amount head in the cutting-oxygen passage just as it was when the cutting-oxygen valve was closed. This is an application of the familiar Pitot tube princie. As above stated, the pick-up tube 21is preferably inclined in the downstream direction from the cutting-oxygen passage to the preheat oxygen This is a convenient construction to manufacture and sufficiently approaches the theoretical Pitot tube construction to give satisfactory results. However, the invention is not limited to a pick-up tube so arranged but includes any kind of a pick-up tube having an inlet openpreheat oxygen to the preheat oxygen passage regardless of whether the cutting-oxygen valve is open or closed.

I claim:

1. In a gas cutting torch in which a cu tingoxygen passage in the torch controlled by a cutpreheat oxygen oxygen from the upstream side of fuel gas e a fuel gas hose deliver the tapped as to a. mixin zone where they form a combustible gas mixture which is fed to the preheating flames that are projected passage which taps a quantity of cutting-oxygen passage at the the cutting-oxygen valve and a supplied by diameter of the cutting-oxygen passage and having an inlet opening facing upstream in the cut-- natructed and open or closed.

3. In a gas cutting torch in which a cuttingoxygen passage in the torch controlled by acutv ting-oxygen valve and supplied by an oxygen hose delivers cutting-oxygen to the torch tip for discharge thereby, and in which a preheat oxygen passage which taps a quantity of oxygen from the cutting-oxygen passage at the upstream side of the cutting-oxygen valve and a fuel gas passage supplied by a fuel gas hosedeliver the tapped preheat oxygen and. the fuel gas to a mixing zone where they form a combustible gas mixture which is fed to the preheating flames that are projected from the torch tip, the improvement which comprises a tube which discharges into the preheat oxygen passage and which has a bevelled inner end projecting into the cutting-oxygen passage where the preheat oxygen is tapped from it, said tube being of smaller outside diameter than the diameter of the cutting-oxygen passage, and said bevelled end of the tube providing an inlet opening facing upstream in the cutting-oxygen passage whereby the tube delivers to the preheat oxygen passage an amount of oxygen which remains substantially constant whether the cutting-oxygen valve is open or closed.

4. In a gas cutting torch in which a cuttingoxygen passage in the torch controlled by a cute ting-oxygen valve and supplied by an oxygen hose delivers cutting-oxygen to the torch tip for discharge thereby, and in which a preheat oxygen I passage which taps a quantity of oxygen from the cutting-oxygen passage at the upstream side of the cutting-oxygen valve and a fuel gas passage supplied by a fuel gas hose deliver the tapped preheat oxygen and the fuel gas to a mixing zone where they form a combustible gas mixture which is fed to the preheating flames that are projected from the torch tip, the improvement which comprises a tube which discharges into the preheat oxygen passage and a portion of which projects into the cutting-oxygen passage wherethe preheat oxygen is tapped from it, the tube being of smaller outside diameter than the diameter of the cutting-oxygen passage and inclined in the downstream direction from the cutting-oxygen passage to the preheat oxygen passage, said tube having an inlet opening in the cutting-oxygen passage and being constructed and arranged to deliver to the preheat oxygen passage an amount of oxygen which remains substantially constant whether the cutting-oxygen valve *is open or closed.

5. A gas torch in accordance with claim 4 in which the inlet end of said tube is bevelled to form an inlet opening lying in a plane substantially at right angles to the axis'of the cuttingoxygen passage and which faces upstream in the cutting-oxygen passage.

6; In a gas cutting torch a body portion having a preheat oxygen passage and a cutting-oxygen passage therein, a portion of the cutting-oxygen passage being substantially parallel with a portion of the preheat oxygen passage, a bore extending transversely into the body portion from one side thereof and intersecting said portion of one passage and meeting said portion of the other passage, the bore being of smaller diameter than said portion of the cutting-oxygen passage, a tube inserted into said bore with a snug fit and communicating at one end with said portion of the preheat oxygen passage, the other end of said tube projecting into the cutting-oxygen passage tion of the preheat oxygen passage, a bore extending transversely into the body portion from one side thereof and intersecting said portion of one v passage and meeting said portion of the other passage, the bore being of smaller diameter than said portion of the cutting-oxygen passage, a tube inserted into said bore with a snug fit and communicating atone end with said portion of'the preheat oxygen passage, the tube having a bevelled other end projecting into the cutting-oxy gen passage and forming an inlet opening facing upstream therein, and a member closing the outer end of said bore.

8. In a gas cutting torch a body portion having a preheat oxygen passage and a cutting-oxygen passage therein, a portion of the cutting-oxygen passage being substantially parallel with a portion of the preheat oxygen passage, an inclined bore extending transversely into the body portion from one side thereof and intersecting said portion of one passage and meeting said portion of the other passage, the inclination of the 'bore being in the downstream direction of the bodyportion from the cutting-oxygen passage to'the preheat oxygen passage, said bore being of smaller diameter than said portion of the cutting-oxygen passage; an inclined tube inserted into said tube with a snug fit and with one end portion projecting into the cutting-oxygen passage and with its other end communicating with said portion of the preheat oxygen passage, and. a member closing the outer end of'said bore.

9. In a gas cutting torch a body portion havin a preheat oxygen passage and a cutting-oxygen passage therein, a portion of the cutting-oxygen passage-being substantially parallel with a portion of the preheat oxygen passage, an inclined bore extending transversely into the body portion from one side thereof and intersecting said portion of one passage and meeting said portion of the other passage, the inclination of the bore REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,379,178 Good May 24, 1921 1,971,008 Kehl Aug. 21, 1934 2,335,987 Young Dec. ,7, 1943 2,399,979

Betz May 7, 1946 

